1. Field of the Invention
The present invention relates to semiconductor image sensors and methods for fabricating the same.
2. Description of the Related Art
In recent years, as electronic devices have become smaller, thinner and lighter, there has been a growing demand for high-density packaging of semiconductor components. Because of this demand together with the high degree of integration achieved by the development of fine processing technology, semiconductor imaging elements, in particular, are being strongly required to shift from a conventional package type, in which a semiconductor imaging element is incorporated into a package, to another type, in which a semiconductor imaging element as a bare chip is directly mounted onto an electronic device.
For example, Japanese Laid-Open Publication No. 2004-111792 discloses a semiconductor package, which includes no through-hole conductors so as to be reduced in thickness, and a method for fabricating the package. This conventional semiconductor image sensor has a device area on one surface thereof and includes a semiconductor substrate having therein connection pads which are connected with the device area, a supporting substrate provided to one surface of the semiconductor substrate, external electrodes (solder balls) provided to the other surface of the semiconductor substrate, and connection means partially extended beyond the periphery of the semiconductor substrate to establish electrical connection between the connection pads and the external electrodes.
In the above-described first conventional example, an imaging area is provided on the one surface of the semiconductor image sensor, while the supporting substrate is provided to the one surface of the semiconductor substrate having the connection pads that are connected with the imaging area, and cylindrical electrodes are formed to the other surface of the semiconductor substrate. This structure allows the package to become thinner. In addition, since the connection means for electrically connecting the connection pads and the cylindrical electrodes are partially extended beyond the periphery of the semiconductor substrate, the structure with no through-hole conductors is realized.
Also, Japanese Laid-Open Publication No. 05-102449 discloses a solid-state image sensor, in which despite its transparent-resin-encapsulated structure, occurrence of flares, smears and the like is suppressed, and a method for fabricating the sensor. According to this second conventional example, the solid-state image sensor, in which wiring is provided on a lead frame, is entirely encapsulated by a transparent resin. Furthermore, at least the part of the outer surfaces of the transparent resin other than the surface thereof corresponding to an effective pixel area is covered with a black resin. The method for fabricating this solid-state image sensor includes: the step of encapsulating by the transparent resin the entire solid-state image sensor having the wiring provided on the lead frame; the step of covering the entire transparent resin by the black resin; and the step of removing part of the black resin existing above the effective pixel area in the solid-state image sensor.